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NOTICE: This document contains information oi a prelim inary nature. It Is subject to revision or correction and therefore does not represent a final report.

This report provides the results of work carried out in support of the U.S. Nuclear Regulatory Commission Accident Management Research Program to develop a technical basis for evaluating the effectiveness and feasibility of current and proposed strategies for boiling water reactor (BWR) severe accident managemenl First. the findings of an assessment of the current status of accident management strategies for the mitigation of in-vessel events for BWR severe accident sequences are described. This includes a review of the BWR Owners' Group Emergency Procedure Guidelines (EPGs) to detennine the extent to which they currently address the characteristic events of an unmitigated severe accident and to provide the basis for 111 recommendations for enhancement of accident management procedures. Second. where considered necessary. new candidate accident management strategies are proposed for mitigation of the late-phase (after core damage has occurred) events. Finally. recommendations are made for consideration of additional strategies where warranted. and two of the four candidate strategies identified by this effort are assessed in detail: (1) preparation of a boron solution for reactor vessel refill should control blade damage occur during a period of temporary core dryout and (2) containment flooding to maintain the core debris within the reactor vessel if the injection systems cannot be restored.